Catheter assemblies, and particularly catheter assemblies for use in hemodialysis, are known that have one, two or more lumens extending from a distal end to a proximal end, where the distal end is placed in a blood vessel of a patient, such as the jugular vein, with the proximal end extending from the patient for each lumen to be connected to a respective conduit of a hemodialysis machine. Customarily, each lumen of the catheter assembly is first connected to a respective extension tube within a hub body, and the extension tube is terminated in a luer connector to facilitate connection with and disconnection from the conduit of the hemodialysis machine and commonly the extension tube has disposed therealong a clamp, such as a Roberts clamp, for temporarily closing the conduit when necessary. Implanted catheter assemblies are connected to medical apparatus such as hemodialysis apparatus through the luer connectors, and then disconnected therefrom, all through many cycles; such connection and disconnection involves the catheter assembly undergoing many cycles of stress and strain especially focused at the proximal end where the catheter proximal end enters the hub which connects the catheter lumens to respective extension tubes, or where a single lumen catheter enters its luer connector directly instead of via a hub and extension tube.
It is desired to provide an assurance against occluding or kinking of the catheter lumens, as well as greater strength, at the connection of the catheter and the hub, or at the connection of a single lumen catheter luer connection where no hub is utilized.
Certain catheter assemblies, termed PICC catheters (for peripherally inserted central catheters), are implanted through a vessel entry on an arm of the patient, known as axillary placement. But, usually, the catheter assembly is secured to the torso of the patient in a manner to prevent any dislocation of the distal tips of the catheter lumens from any movement along the vessel after initial placement at the catheterization site. This manner of securement is usually accomplished by a process termed tunneling, in which the proximal portion of the catheter assembly outside of the vessel is tunneled subcutaneously near the vessel entry site, typically beneath the clavicle of the patient, whereafter the hub is sutured or otherwise secured to the patient. By this process, during the connection with and disconnection from the hemodialysis machine of the extension tubes, there is no stress or strain passed to the distal end of the catheter assembly that might tend to dislodge the distal lumen tips from the desired location along the vessel.
The orientation of the tunneled portion of the catheter assembly is not axially aligned with the distal portion of the catheter assembly and in fact a relatively sharp bend may be made in the catheter assembly distally of the tunneled portion during placement.
It is desired to provide an assurance against occluding or kinking in the sharp bend between the tunnel's distal end and the venotomy.
When a catheter is being inserted vascularly into a patient, and the incision is made into the vessel at the access site or venotomy, and the introducer sheath is placed to maintain open the vascular access site for introduction of the catheter assembly, the catheter assembly is initially inserted along the guide wire through the introducer sheath. During this process, aspiration of blood occurs and measures must be taken to temporarily stop the flow, such as manually closing off the proximal end of the introducer sheath. But as the catheter is inserted into the sheath, additional blood again begins to extrude from the sheath.
It is desired to provide a means for minimizing the flow of blood as the catheter assembly is inserted through the introducer sheath and into the vessel, and also after catheter insertion as the introducer sheath is removed from the access site.
Catheters are conventionally produced in various sizes depending on desired uses, and their outer diameters are measured in units termed “french” or “F”, with one F equaling 0.013 inches or 0.32 millimeters. The largest sized catheters utilized for vascular placement may have an outer diameter of about 17 F, while the smallest sized dual-lumen catheters presently preferred are 5 F although smaller sized single lumen catheters are known. Certain problems are associated with catheters after they are vascularly in a patient; for example, development of phlebitis and thrombosis is known when the catheter outer diameter is almost the same size as the inner diameter of the vessel within which it is implanted.
It is desired to provide a catheter with a very small outer diameter, especially a dual lumen catheter, thereby minimizing the tendency of phlebitis or thrombosis or the like, to develop.